Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control
no-cache, no-store, max-age=0, must-revalidate
Directive
Value
Meaning
no-cache
—
Cache but always revalidate first
no-store
—
Never cache this response
max-age
0
Cache for 0 seconds
must-revalidate
—
Must recheck with server after expiry
B
Page Weight Budget
1.3 MB transferred, 74 requests
REVIEW
1.3 MB transferred, 74 requests
Info::
✓
Page weighs 5.2 MB (1.3 MB transferred)
Warning::
!
JavaScript is 980 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 980 KB
Info::
i
74 HTTP requests
Info::
i
Estimated 0.27 g CO2 per page load
1.3 MBtransferred
74 requests
0.27 g CO2 per page load
JavaScript980.2 KiB76%
CSS176.7 KiB14%
HTML60.8 KiB5%
Fonts28.1 KiB2%
Other26.3 KiB2%
Other15.5 KiB1%
Other7.0 KiB1%
Images1.2 KiB0%
Other341 B0%
02.4 MB4.9 MB
Under budget
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Why this matters
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A
Image Optimization
3 images, 0 KB saveable
PASS
3 images, 0 KB saveable
Info::
✓
All images are well-optimized
3images1 KB
0oversized-0 KB
2legacy format
0missing dimensionsCLS risk
A+
Font Loading
2 fonts (28 KB)
PASS
2 fonts (28 KB)
Info::
i
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
28 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
KFOmCnqEu92Fr1Mu4mxPKTU...ttfswap
Size14 KB
Load time24 ms
Start298 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
KFOlCnqEu92Fr1MmEU9fBBc...ttfswap
Size14 KB
Load time12 ms
Start310 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Optimization checklist
Preload critical fonts (priority=high)
Use woff2 format for all fonts
Set font-display to swap, optional, or fallback
Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~8 KB and ~16 ms
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Google Cloud
Network Waterfall
74 requests over 3468ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party3792ms · 1035KB · €41/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
m.youtube.com
m.youtube.com
Other
1635ms
435 KB
54%
€18/mo
Costly
Unattributable
Unattributable
Other
853ms
0 KB
—
€9/mo
Costly
m.youtube.com
m.youtube.com
Other
478ms
60 KB
—
€5/mo
Costly
m.youtube.com
m.youtube.com
Other
257ms
417 KB
74%
€3/mo
Costly
m.youtube.com
m.youtube.com
Other
151ms
3 KB
—
€2/mo
Optional
m.youtube.com
m.youtube.com
Other
145ms
17 KB
—
€2/mo
Optional
m.youtube.com
m.youtube.com
Other
127ms
77 KB
77%
€1/mo
Optional
www.google.com
www.google.com
Other
97ms
23 KB
—
€1/mo
Optional
m.youtube.com
m.youtube.com
Other
50ms
2 KB
—
€1/mo
Optional
m.youtube.com
Other
Costly
Execution1635ms
Transfer435 KB
Unused54%
Monthly Cost€18/mo
Unattributable
Other
Costly
Execution853ms
Transfer0 KB
Monthly Cost€9/mo
m.youtube.com
Other
Costly
Execution478ms
Transfer60 KB
Monthly Cost€5/mo
m.youtube.com
Other
Costly
Execution257ms
Transfer417 KB
Unused74%
Monthly Cost€3/mo
m.youtube.com
Other
Optional
Execution151ms
Transfer3 KB
Monthly Cost€2/mo
m.youtube.com
Other
Optional
Execution145ms
Transfer17 KB
Monthly Cost€2/mo
m.youtube.com
Other
Optional
Execution127ms
Transfer77 KB
Unused77%
Monthly Cost€1/mo
www.google.com
Other
Optional
Execution97ms
Transfer23 KB
Monthly Cost€1/mo
m.youtube.com
Other
Optional
Execution50ms
Transfer2 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
m.youtube.com adds 1635ms and costs ~€18/month
Unattributable adds 853ms and costs ~€9/month
m.youtube.com adds 478ms and costs ~€5/month
m.youtube.com adds 257ms and costs ~€3/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
m.youtube.com takes 1635ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of m.youtube.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Unattributable takes 853ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
m.youtube.com takes 478ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
m.youtube.com takes 257ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
74% of m.youtube.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
77% of m.youtube.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.